Asymmetrical Driver Circuits for Buck Converter Efficiency
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Solution Overview
Problem
Conventional synchronous buck converters suffer from inefficiencies that result in energy loss as unwanted heat, requiring oversized power supplies and increasing costs due to internal energy dissipation.
Innovation Solution
Implementing asymmetrical driver circuits with different current drive capabilities to control high and low side switches at varying speeds, and dynamically adjusting the number of voltage converter phases in response to load changes to optimize power delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional symmetrical driver circuits are used to control high and low side switches, then the control circuitry is simple and balanced, but energy losses increase due to slower switching speeds and diode recovery losses
Solution Approach 1:
The patent applies asymmetry by using different driver circuits with different current drive capabilities for the high side switch and low side switch. The first driver circuit has a first current drive capability while the second driver circuit has a second current drive capability that is greater than the first, creating intentional asymmetry in the driver configuration to optimize switching performance and reduce energy losses.
Solution Approach 2:
The patent applies local quality by tailoring the driver circuit characteristics to the specific requirements of each switch. The low side switch receives a driver with higher current drive capability to achieve faster switching, while the high side switch receives a driver with lower current drive capability, optimizing each location's performance based on its specific needs.
2Loss of energy
If the low side switch transitions slowly between ON and OFF states, then the driver circuit is simple, but diode recovery losses increase reducing efficiency
Solution Approach 1:
The patent applies parameter changes by varying the current drive capability parameter of the driver circuits. The second driver circuit is designed with a higher current drive capability parameter than the first driver circuit, which directly changes the switching speed parameter of the low side switch to reduce diode recovery losses.
3Reliability
If oversized power supplies are used to account for buck converter losses, then reliability is improved, but cost increases
Solution Approach 1:
The patent converts the harmful effect of diode recovery losses into a benefit by using asymmetrical driver circuits to minimize these losses. By optimizing the switching speed through unequal current drive capabilities, the system reduces energy waste and improves overall efficiency, eliminating the need for oversized power supplies.
Data Source
AI summary
A power supply system includes a first driver circuit to control a corresponding switching of a first switch device and a second switch device in the power supply system via different drive circuits. To reduce losses and thus improve efficiency of the power supply system, a first driver circuit can be configured to initiate a faster rate of transitioning the first switch device between ON and OFF states than a second driver initiates transitioning of the second switch device between ON and OFF states. To reduce the effects of introducing unwanted ripple voltage on an output signal used to drive a dynamic load, a controller in the power supply system can be configured to initiate shedding or adding of multiple voltage converter phases at the same time when load requirements cross a threshold value.